1. Field of the Invention
The present invention is directed to an improved hydrostatic bearing for a rotatable shaft and more specifically, to a hydrostatic bearing with improved means for stabilizing the shaft and for reducing the lubricating fluid leakage flow rate from the hydrostatic bearing.
2. Description of the Prior Art
The performance of rocket engines utilizing liquid propellants is related to the efficiency of the propellant tubopumps. Turbopump efficiency is frequently dependent on its operating speed; however, an optimum speed is sometimes difficult to realize if rolling ball element bearings are used. Operating speeds in some cases are limited below the point of maximum efficiency by the life-limiting relationship of rolling element bearing DN (diameter.times.rotative speed) and less frequently by rotor critical speed. Substitution of hydrostatic bearings for rolling element bearings provides a solution to this problem because hydrostatic bearings have no DN limit and the rotor can be sized for critical speed margin without regard to bearing DN. An increased operating speed also reduce turbopump size and weight.
Conventional hydrostatic bearings utilize a number of feeding recesses for lubricating fluid, along the circumference of the bearing. (See "Hydrostatic Bearings for Cryogenic Rocket Engine Turbopumps" by J. M. Reddecliff and J. H. Vohr, Journal of Lubrication Technology, July 1969.) The feeding recesses provide pockets for lubricating fluid, allowing the build up of more effective hydrostatic pressure and interrupting circumferential flow of lubricating fluid, thus helping to stabilize the shaft. However, at very high speeds stability problems exist and there is often excessive leakage of lubricating fluid from the hydrostatic bearing.